Marc Leduc, 56, appeared in an Ottawa court Thursday morning and he was formally charged in the deaths of Pamela Kosmack, 39, and Leeanne Lawson, 23.
Kosmack's family and Lawson's friends were among those in the courtroom. Leduc was ordered not to contact the relatives of Kosmack or Lawson while he's in custody.
His next court appearance is scheduled for March 1, with defence lawyer Ian Carter saying he won't be seeking bail.
"Obviously the allegations are serious and very shocking," Carter said.
"There was a significant amount of evidence generated during this investigation . . . once I get that, I will be able to assess it and say something more at that stage."
Leduc was arrested Wednesday at the Ottawa-Carleton Detention Centre. He was in police custody facing eight charges connected to an alleged sexual assault in early November at a west Ottawa apartment building.
He is accused of breaking into the apartment of a 19-year-old woman who was sleeping and sexually assaulting her while brandishing a knife.
Police say DNA played role in case
Ottawa police Chief Charles Bordeleau said Thursday DNA played a role in the investigation, but declined to discuss the details, because it is an ongoing investigation.
Kosmack was found beaten to death in June 2008 on a bike path near Lincoln Fields transit station in west Ottawa. Lawson was found dead in a parking lot in Ottawa's Lowertown neighbourhood in September 2011.
Shortly after Lawson's death, then police Chief Vern White issued a warning to sex-trade workers, noting a pattern linking recent murders. Police had told CBC News more than a year ago they believed a suspect who killed multiple sex workers may be linked to the unsolved homicide of Kosmack.
But Bordeleau and Major Crimes Staff Sgt. Rob Drummond said Thursday police would not talk about possible connections to any other unsolved cases.
Bordeleau said there are four other unsolved homicides connected to sex-trade workers, but he would not discuss any links between those cases.
A day earlier, Kosmack's brother-in-law, Darrin Murch, said it was a "bittersweet" day learning about the arrest.
"It's a good day that after four years, eight months and two days, somebody's finally been charged with the murder," said Murch. "We're just trying to move on, and now my sister-in-law can rest in peace," he said.